The NBA and its players, trying to hammer out a labor agreement, are on a fast break. Trouble is, they may be racing in opposite directions.

Players earned average salaries of $500,000 last season, yet they are asking for more, including larger paychecks and a free marketplace.

Team owners, mindful of how the league seemed on the verge of collapse only five years ago, want to hold the line.

Talks have been going on since February with little progress. The last session, held Wednesday, dragged on for three hours ''but went nowhere,'' according to one league representative.

Despite a lack of movement, neither side reports feeling the pressure of a deadline. The start of the regular season is still nearly four months away -- plenty of time, the players say, to iron out differences.

Details of the negotiating sessions have been hush-hush. ''We're not going to do our negotiating in the newspapers,'' Commissioner David Stern said. ''All the yelling we are going to do, we're going to do behind closed doors.'' One source inside the players association, who requested anonymity, said the players and owners are discussing some maverick ideas.

Those proposals are said to include doing away with the annual college player draft, dramatically raising the amount of money teams may spend on salaries and allowing players to peddle themselves to the highest bidder -- with no strings attached -- once during their careers.

Neither side would confirm those proposals. The players appear unified, though none publicly have raised the threat of a strike.

''I know I'm not pushing for a strike,'' Los Angeles Lakers guard Earvin ''Magic'' Johnson said. ''But I think all of the players are ready for a hard battle.''

There never has been a strike in the NBA's 40-year history. The last contract between the players union and the owners, reached in April 1983, came nearly a year after the previous agreement had expired and only a few days before a player-imposed strike deadline. That contract ran out at the end of this year's NBA Finals.

Reaching a new agreement may be a long and arduous process, what with the players asking for a bigger share of newfound riches by the NBA.

The league, by its admission, is on a financial high, its popularity rejuvenated by charismatic stars such as Michael Jordan, Larry Bird and Akeem Olajuwon. Revenue from television, ticket sales and merchandising has grown from $120 million in 1983 to about $250 million last season, according to the league.

Four expansion teams, including the Orlando Magic, are poised to pay a combined entry fee of $130 million over the next two years.

Salaries have escalated, too, from an average of $260,000 four years ago to nearly $500,000 last season, league officials say. Yet the players are not satisfied, even though their last contract netted them 53 percent of the league's annual gross revenues.

Most league observers see the talks as critical to the continued success of the league.

''The talks are very significant,'' said Pat Williams, president and general manager of the Orlando Magic. ''You have to have a fair agreement for both sides if the league is to prosper.''

It is difficult to say what, if any, effect a new agreement will have on the Magic and the other expansion teams. The four new teams will have a stake in the negotiations. The new agreement likely will cover four years and will affect them as they enter the league.

''We all will be playing by the same rules,'' Williams said.

In their most ambitious set of demands, seen as a starting point for the talks, the players are seeking:

An end to the college player draft. In a radical move that could change professional sports, prospective NBA players would become free agents.

The owners argue that this would lead to a collapse of the league, for only the wealthiest teams would be able to bid for the best talent. The players contend that ending the draft is the only way to establish a free marketplace. Unrestricted freedom of movement for veterans whose contracts have expired. Players argue that true free agency does not exist in the NBA. Once a player's contract has expired, he may negotiate with another team but the current club has the right of ''first refusal,'' meaning it has the option of matching any offer and retaining the rights to the player.

Players say that because of the right of first refusal, most clubs don't attempt to sign top free agents.

The NBA Players Association claims that in 1986, only five of 95 free agents were offered contracts by other clubs.

Contracts to free agents this year cannot be extended until a collective bargaining agreement is reached.

Owners point to the salary average as proof that the players are being paid their worth.

An end to the salary cap. The cap, which has grown from $3.2 million in 1984 to $4.95 million last season, restricts how much teams are allowed to spend on payrolls.